A church mouse is no ordinary mouse, and Hildegarde—the Mouse Mistress of Saint Bartholemew's—is no ordinary mouse leader. In this charming novel for readers 9 and up from two-time Newbery Medal winner Lois Lowry, it falls to Hildegarde to keep all of the church's mice safe and out of sight. But when a few parishioners report mouse sightings, she and the rest of the church mice suddenly face a most dreadful consequence: the mysterious Great X. And to further complicate things, the annual Blessing of the Animals is fast approaching; St. Bartholemew's will soon be filled with pets—including cats.